A computer model of the human cardiovascular system has been developed for the study of pressure-flow-volume dynamics. The principal purpose of the design is to understand the complex interactions between elements of the circulatory system. Reasonable accuracy of performance has been achieved by basing the elements of the model on physiological and anatomical rather than empirical (curve-fitting) properties of the actual system. The principal components is the time-varying elastance model of the heart. Options for varying physiological states, and multiple acquired and congenital abnormalities are incorporated. Graphic output provides and additional understanding of the model's function.